; From: thinman@netcom.com (Technically Sweet)
; Subject: Another N-dim array package
; Message-ID: <thinmanC47Ipr.L4p@netcom.com>
; Organization: International Foundation for Internal Freedom
; Date: Sat, 20 Mar 1993 21:37:02 GMT

; In contrast to Alan Bawden's cool elegant array package,
; here's my simple one:

(define (make-grid start . dims)
        (if (list? (car dims)) (set! dims (car dims)))
        (let ((v (make-vector (car dims) start)))
                (if (not (null? (cdr dims)))
                        (do ((i 0 (+ i 1))) ((>= i (car dims)))
                                (vector-set! v i
                                        (make-grid start (cdr dims)))))
                v))

; grid n0 n1 n2 ...
(define (grid-ref g . n)
        (if (list? (car n)) (set! n (car n)))
        (if (null? (cdr n))
                (vector-ref g (car n))
                (grid-ref (vector-ref g (car n)) (cdr n))))

; grid value n0 n1 n2 ...
(define (grid-set! g v . n)
        (if (list? (car n)) (set! n (car n)))
        (if (null? (cdr n))
                (vector-set! g (car n) v)
                (grid-set! (vector-ref g (car n)) v (cdr n))))

; tests
(define t (make-grid 0 '(4 5 6)))
(display t)
(grid-set! t 24 '(2 2 3))
(display (grid-ref t '(2 2 3)))

(define u (make-grid #f 2 2))
(display t)
(grid-set! t #t 1 0)
(display (grid-ref t 1 0))